Luckily for me, markers made my diamonds into rubies:
|colored-in with a regular permanent marker|
|after a couple of "coats" of marker ink, applied with the pen|
|... and slapped onto a quickly-made feather pad|
C'est finis! Took all of, oh, five minutes?
The red came off with nail polish remover later too, so now it can turn into sapphires, or emeralds, or imaginary stones of whatever shades I could wish. I wouldn't do this for sale-able pieces, but it's been great fun for personal costume-y things!